Production of light hydrocarbons



March 2, 1937.

Filed Sept. 16, 1933 Patented Mar. '2, 1937 PATENT A oFFlcE 2,012,108 i PRODUCTION or ucar maocAaBoNs Eugene J. Houdry, Woodbury, N. J., assignor to Houdry Process Corporation, Dover, Dei., a corporation of Delaware Application 'September 16,1933, Serial No. 689,694

4 Claims.

This invention relates ,to the production of light or W boiling' hydrocarbons including gasoline from high boiling hydrocarbons such as crude oil, crude oil distillates, residual oils from cracking or transforming operations, tarry residues, and the like. Morevparticularly, it involves the elimination, from time to time, by solvent extractionor otherwise, of certain undesirable components in the material undergoing treatment.

It is well known that the results obtained in the cracking or transforming of heavy hydrocarbons vary greatly with diierent charging stocks. For instance, transformation of liquid hydrocarbons obtained from thedistillation of coal requires higher 'temperatures and higher pressures than is the case with natural liquid hydrocarbons, such as crude oil and its distillates. However, crude oils and their distillates or residuums show great differences as to yield and quantity and quality of light products produced. For example, given the same apparatus and the same conditions of operation, a Mid-Continent stock will give 23% gasoline, while a Pennsylvania stock gives 33% gasoline, and a special stock, such as petrolatum, gives 55% gasoline. Numerous observations and comparisons of the analyses of charging stocks and of residues after transformation and separation of light hydrocarbons demonstrate that the components which are able to be transformed into light hydrocarbons decrease in proportion with each pass through the apparatus, while the products which are not transformed increase in proportion. By segregation of components, it has been further determined that a part only are capable of being transformed, while another'part is practically untouched by the transforming operation. This means that the operations on a large part of the material arepractically wasted, and, what is far Worse, this part has a detrimental eect on the operations themselves, because, while such part of the material is not producing the desired product, it doesnot remain inert but produces gases and carbon. The carbon is left-on the apparatus, requiring more frequent cleaning and giving poor heat exchange, while the qualityof the desired products isimpaired, since the car- -bon deposit acts as a catalyst which has a tendency toincrease the formation of gums and guminy constituents in the low boiling hydrocarbons. While such results Vhave been recognized to a certain extent in connection with thermal cracking operations, there has been a tendency to ignore them. A

When using catalytic transforming operations, such as those disclosed in certain of my cepending applications involving the use of catalytic adsorptive masses made up in whole or in part of materials from the group comprising silicates of alumina or clayey materials, such for example (ci. 19e- 52) as activated hydrosilicate of alumina in molded form, at temperatures between775 and 925 F., the effect of rapid carbon deposit is very serious, since the activity of the'catalyst is quickly reduced and increased temperatures and pressures cannot be used without impairing the quality and/or the yield of the product. matter, a residual oil from the fifth pass on Mid- Continent (Ranger) gas oil was separated, by the action of solvents, into two fractions, an aliphatic fraction and an aromatic fraction. The aliphatic fraction had the following character- When subjected to the catalytic transforming operation, it produced a good yield of gasoline with a very small deposit of coke or carbon on the catalyst. The ratio of gasoline production to coky depositwas 23.71z1, and the ratio of gasoline to`gas was 5.63:1. Noattempt was made to secure the highest yield, since the purpose of the experiment was to check the action of the catalyst on both fractions under the same conditions. Nevertheless, the gasoline produced was 20% of the aliphatic fraction.

To test the y The aromatic fraction had the following characteristics:

Speciflc gravity 0.9792 Distillation (IBP) 443 5% 471 10% 481 15% 492 20% '499 30% 508 40% 524 536 550l v 571 607 659 Dry point 676 Residue 5.5%

When treated undervexactly the same conditions as the aliphatic fraction, the aromatic fraction gave a yield of only 1.9% gasoline. ',I'he vvratior of gasoline to eckyl deposit was 034:1, and the ratio of' gasoline to gas 1.68: 1. 'I'he aromatic fraction left as poison a coky deposit on the catalyst amounting to 2.02% of the mass in producing less than that percentage of gasoline, while, with the aliphatic fraction, the cokv deposit was 0.78% in producing gasoline. If we consider that the stock contained 45% in volume of the alil0 phatic fraction and 55% of the aromatic fraction,

it is evident that processing of the entire stockformed by a catalytic operation of the type here-A tofore described, into gasoline, but that the residual oil from the first transformation, as well as residual oils from later passes, contain Aaromatic fractions which are of the kind described in the preceding paragraph, namely, very refractory and breaking up only into coke and gas. Accordingly, the invention involves a transforming or cracking operation on crude oil distillates, followed by solvent or other treatment of residual material to separate and discard the unfavorable components, the later transforming operations being conducted in each instance upon the favorable constituents only. If the bottoms from the skimming or topping operation are to be transformed,` or if the distillates are mixed with the bottoms, it is preferable to first submit this material to extraction of the heavier constituents, since the asphaltic and tarry materials Vare often detrimental to catalytic transforming masses, especially the activated hydrosilicate of alumina referred to above. l able methods maybe utilized to make amore or 215 less complete separation ofthe desirable andl the undesirable constituents of the stock to be tra-nsformed. 'Ihe use of solvents is effective. A certain amount of separation is also possible by purely physical means, as by fractionation.

In order to illustrate the invention and the .manner of its application, drawings in the form `of ow charts are provided, in which: I Fig. l shows one way or now chart forqtransforming crude oil; and- Fig. 2 shows an alternate way or flow chart. In Fig. 1, the crude petroleum is rst subjected to .a topping operation and the products separated into straight run gasoline, one orv more side streams such as a middle or gas oil cut, and

I obottoms. The straight run gasoline is set aside for use or for` blending with the gasoline produced in the subsequent transforming operations. The" middle cut or side stream is subjected to atrans- I forming'or cracking operation, preferably the catalytic treatment at '775 to 925 F., at low or atmospheric pressure, and in contact with activated hydrosilicate. of alumina in molded form, as previously specified. The gasoline resulting from this operation is set aside or blended with 7o the previous straight run gasoline.' The residual material is then subjectedA'to a solvent or other treatment to remove thev constituents unfavorable to further transforming operations. At this time, the bottoms, as indicated by the broken 7s line a oriv the chart, may be added to the residual Any known or suitmaterial from the first transforming operation just' prior to the solvent or other treatment; or a preferred way is indicated by solid lines, in which the bottoms are subjected to a separate solvent or other treatment on account of the large con- 5 tent 'of asphaltic and tarry material which n'or-4 mally will require a somewhat different treatment than that given to the residual oil from the transforming operation. The favorable constituents from this treatment would be added to 10 the middle cut in advance of the transforming or cracking operation as by the solid line b on the chart, or to the favorable constituents from the transforming operation as by the solid line c and both then subjected to a. second pass or catalytic 15 transforming operation. The resulting gasoline is set aside or blended with the previously segregated gasoline. The residual material is subjected to a solvent or other treatment to discard unfavorable constituents; the favorable constit- 20 uents are subjected toanother pass or catalytic transforming operation; and. .the process may continue until the desired yield of gasoline is secured. l

The operation indicated in Fig. 2 distinguishes 25 from that just described in that there are but two products l'of the topping operation, namely, the

straight run gasoline and residual material, n0 side cut in the gas oil boiling range being taken. The residual material, containing a considerable 30 quantity of asphaltic and tarry constituents, is subjected to a solventeor" other treatment to elimmais, o far as possible, the heavy constituents and aromatic components. The favorable constituents, comprising the aliphatic fraction, are 35 then subjected to acatalytic transforming opera tion of the described type. The' gasoline and other light products are segregated from the residual material, and the latter is subjected to an other solvent or other treatment to remove the unfavorable constituents, whereupon the favorable constituents are subjected to a second pass or catalytic transformingv operation, followed by a separation lof products into gasoline and residual material, the process being continued until 46 the desired yield of gasoline is produced.

Any known means for effecting the solvent or other separation of desirable and undesirable components may be utilized, theobject being to discard, so far as possible, from subsequent cata- 50 lytic transforming operations, the heavier and more refractory components,l including the aromatic fraction. Various solvents have been pro-`J posed, especially in connection with the treatment of lubricating oils, which are capable of forming 65 a two-layer system and are suitable for this purpose. Onelayer will be more aromatic and the other more aliphatic than the original oil. Among the solvents which are' useful in applying the x present invention are liquid SO2, ethylene chlor- 00 hydrin, glycol mono-acetate or di-acetate, glycol monoethyl ether, glycerol,d1 or tri-acetate, lactic acid nitrll, diethy1tartrate, furfurol, aniline,

toluidine, phenylhaydrazine, etc. Afcertain degreeof separation is also possible byfractionation 05 into close cuts and-by a judicious combining of the cuts. a f1 I claim as my invention:

1. The process of producing light or low boilingV hydrocarbons from'crude oil or the equivalent .7,0 which comprises topping the crude oil to remove the straight run lgasoline and dividing the remainder by fractionation into a middle cut and bottoms, removing from the bottoms at least a part of the asphaltic and tarry aromaticconstitu- Z5 ents, adding the remaining or favorable parts to the middle cut, transforming the resulting middle cut mixture to produce the desired light products and a residual oil, removing'from the residual oil at least some of the more aromatic constituents thereof, unfavorable to further transformations, and transforming the remainingv or favorable parts from the residual oil into the desired light products and a residual oil suitable for a further removing and transforming operation. y

' 2. The process of producing light or low boiling hydrocarbons from crude ,oil or the equivalent which comprises topping the crude oil to remove the straight run gasoline, catalytically transforme4 ing a middle cut from the topping operation to produce the desired light products and a residual oil, removing from theresidual oil at least some of the aromatic constituents unfavorable to further transformations by solvent treatment, catalytically transforming the remainingor favorable parts of the residual oil into the desired light products and a residual oil suitable for further removing and transforming operations, removing from the bottoms from the topping operation at least a part of the asphaltic and tarry constituents by solvent treatment ina stepseparate and distinct from the first removing step, land 'adding the remaining or favorable parts of the last removing step to the favorable parts from the first removing operation in advance of the second' line and a residual oil by the yaction of an adsorptive contact mass of the clay type, adding the bottoms from the topping operation to the residual oil, removing from the combined residual oil and bottoms some, of the more aromatic constituents thereof, which rapidly impair the activity of the contact material, and transforming the remainder or favorable portion of the residual oil andy bottoms by the action of an adsorptive contact mass of the clay type into the desired light products and residual oil.

4. The process of producing light or low boiling hydrocarbons from crude-oil or the lequivalent which comprises topping the crude oil to remove the straight run gasoline, transforming a middle cut from the topping voperation at low pressure and temperature into the desired light products and a residual oil in the presence of'an adsorptive contact mass composed in whole or in part of activated hydrosilicate of alumina, removing from the residual oil at least a part of the constituents unfavorable to further catalytic transformations including the aromatics, transforming the remaining or favorable parts. of the residual oil in the presence of contact mass of the same type as the aforesaid into the desired light products and a second residual oil suitable for further removing and transforming operations, removing from the bottoms from the topping operation at least a part of the`asphaltic and tarry aromatic constituents, and adding the remaining or favorable part of the last removing step to one of the aforementioned favorable portions in advance of transforming the same.

EUGENE J.A HOUDRY. 

